Jumping Oak Gall on Bur Oak

Asked August 25, 2013, 2:06 PM EDT

Maybe 15-20% of the leaves on my 6" Diameter Bur Oak appear to be infected with what I think is Jumping Oak Gall. According to what I read, this is supposedly not a problem but it gets worse every year, interferes with additional rounds of growth and it seems to have spread to another tree about 75 ft away. How can I control this?

Denton County Texas

5 Responses

Hi there,

thanks for asking about your oak galls. first off, the tree is not infected by bacteria or a virus. the galls are caused by a parasitic wasp. the wasp stings the leaf and lays an egg. the tree sees it as a foreign body and develops a cyst around the egg; that's what the galls are. there is really no good or economical way to control the wasps themselves so we recommend that you treat the tree with a chemical called Imidacloprid. it is a drench you mix with water and pour at the drip line of the tree. several companies like Bayer, Ortho and Fertilome have products containing the chemical in a drench. i would recommend twice a year but follow the label instructions. if you have any more questions call 940-349-2887.

Two times a year...when? Does September and March work?

I would recommend once in the spring as you see the tree to begin to green up and again July or August. depending on the weather September may be too late in the year. once it starts turning cool the sap in the tree begins to run the opposite direction and drenching has no effect.

Thanks for the info. It seems to have been somewhat successful. Although some of the leaves were damaged, it was not as bad as last year and I'm starting to see a second round of growth on most of the branches...definitely better than last year. Thanks again.

good. just keep using the product a few time a year and it will make a big difference.